17. Chloe x Halle, 'The Two of Us'
Released initially as a single YouTube post, this mixtape from the Beyoncé-approved teenaged sister act flips through styles of R&B like they're Instagram filters, showcasing the duo's spectral harmonies and boundless curiosity. The ornately detailed a cappella "Dum Dum Dum," the funk-tinged two-step "Worries" and the pillowy call-and-response "All I Ever Wanted" play like fascinating glimpses at the duo's scratchpad. Fully realized tracks like the triumphant "Tra Ta Ta" and the gently insistent come-on "Poppy Flower" show how they're already pulling soul in exciting new directions by seemingly operating on the sort of instinct that comes from having a blood relative (not to mention pop's reigning queen) at your side. M.J.